The invention relates to a device having a cylinder including a gripper system for holding a sheet of printable material, the gripper system possessing at least one gripper mounted so as to be pivotable relative to at least one gripper support and being capable of dipping into a channel of the cylinder below the outer jacket contour of the cylinder, and having a control cam for controlling the pivoting of the gripper relative to the gripper support.
Devices of the foregoing type referred to herein have become known heretofore. They include a cylinder having a gripper system with a plurality of grippers, customarily, the grippers projecting over the jacket surface of the cylinder. When the cylinder cooperates with a counter-cylinder, for example, a blanket cylinder, gravure cylinder, flexographic printing cylinder or the like, the counter-cylinder must have a channel for receiving the grippers therein. In order to be able to use a counter-cylinder having a continuous jacket surface, devices have become known wherein the grippers of the gripper system can be dipped into a channel of the cylinder below the outer jacket contour of the cylinder.
The published German Non-prosecuted Patent Application (DE-OS) 16 11 297 discloses a cylinder having a gripper system wherein the dipping movement of the gripper system into a channel of the cylinder below the outer jacket contour of the cylinder is controlled by a cam disk. A further control cam is required in order to pivot the pivotably mounted grippers relative to a gripper support into an opening position and a clamping position. A disadvantage thereof is the elaborate and hence cost-intensive structure of the gripper system.
The published German Non-prosecuted Patent Application (DE-OS) 21 35 714 discloses a cylinder having a radially extending slit wherein there is guided a linearly displaceable clamping bar for holding a sheet of printable material. When the clamping bar is moved into the slit, the sheet of printable material is clamped between the clamping bar and the slit wall. The dipping and clamping movement of the clamping bar is controlled by a stationary control cam.
The published German Patent Document DE 30 49 067 C2 discloses a device wherein, to actuate the grippers of the gripper system, a gripper opening cam and a further control cam for controlling the dipping of the grippers into the channel of the cylinder are provided.
The published European Patent Document EP 0 769 376 B1 discloses a device wherein both a gripper opening cam for opening and closing the dipping grippers and a further control cam for controlling the dipping movement of the dipping grippers are provided. The effort required for constructing the device is correspondingly great.
It is an object of the invention to provide a device having a cylinder including a gripper system of the general type described in the introduction hereto that has a relatively simple structure and operates with functional reliability.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a device comprising a cylinder having a gripper system for holding a sheet of printable material, the gripper system having at least one gripper mounted so as to be pivotable relative to at least one gripper support and being capable of performing a dipping movement into a channel formed in the cylinder below an outer jacket contour thereof, and having a control cam for controlling the pivoting of the gripper relative to the gripper support, the control cam also serving to control the dipping movement of the gripper system into the channel.
In accordance with another feature of the invention, the gripper is drive-connected to a coupler of a swivel-joint transmission.
In accordance with a further feature of the invention, the gripper is connected to the coupler for performing a pivoting movement.
In accordance with an added feature of the invention, the device includes a swivel joint via which the gripper is connected to the coupler.
In accordance with yet another feature of the invention, the gripper is rigidly connected to the coupler of the swivel-joint transmission.
In accordance with yet a further feature of the invention, the gripper support is spring-mounted by at least one spring element.
In accordance with yet an added feature of the invention, the swivel-joint transmission is a four-membered coupler transmission.
In accordance with yet an additional feature of the invention, transmission members of the coupler transmission are of such size, and pivots of the coupler transmission are disposed in such a manner that the gripper, during a last phase of a closing operation thereof, serves to describe a section of a path of movement which is straight and at least approximately perpendicular relative to the gripper support.
In accordance with still another feature of the invention, the gripper support, during the dipping movement of the gripper system, is mounted so as to move exclusively in the direction of the dipping movement in order to avoid relative movements between the gripper and the gripper support.
In accordance with still a further feature of the invention, the device includes a swivel joint forming an axle for articulatedly connecting the gripper to the gripper support.
In accordance with a concomitant aspect of the invention, there is provided a printing press including a device comprising a cylinder having a gripper system for holding a sheet of printable material, the gripper system having at least one gripper mounted so as to be pivotable relative to at least one gripper support and being capable of performing a dipping movement into a channel formed in the cylinder below an outer jacket contour thereof, and having a control cam for controlling the pivoting of the gripper relative to the gripper support, the control cam also serving to control the dipping movement of the gripper system into the channel.
Thus, the device according to the invention comprises a cylinder having a gripper system for retaining a sheet of printable material, for example, a sheet of paper or cardboard. The gripper system possesses at least one gripper mounted pivotably relative to a gripper support, and between the gripper and the gripper support the sheet of printable material to be transferred from the cylinder can be retained with clamping. To control the pivoting movement of the gripper relative to the gripper support, a control cam is provided. The at least one gripper and the at least one gripper support are so formed that they can be dipped into a channel formed in the outer shell or jacket surface of the cylinder, below the outer shell or jacket contour of the cylinder. The device according to the invention has the feature that the control cam is also used to control the dipping movement of the gripper system into the channel, i.e., the control cam serves both for controlling the pivoting of the gripper relative to the gripper support and for controlling the dipping movement of the gripper system into the channel. Because of the dual function of the control cam, the structure of the device according to the invention can be simplified by comparison with heretofore known devices of this general type.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device having a cylinder including a gripper system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: